SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c11e7e1bd558150481aaf4044f68b86a6d02d520eee8a0a970697efdd5e12b7c' 
  AND token = 'Wst5tjkWFWKlnPjgTUyDbjmmtE0EyexJHuxYV7XDFHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}